NASHVILLE - Two of Tennessee's Republican federal officeholders are stepping into the 4th Congressional District race to openly back Republican challenger Scott DesJarlais's bid against incumbent U.S. Rep. Lincoln Davis, D-Tenn.

U.S. Sen. Bob Corker, R-Tenn., endorsed the Jasper physician on Wednesday while U.S. Rep. Marsha Blackburn, R-Tenn., weighed in with her own thumbs-up today, according to DesJarlais campaign news releases.

"Our nation has some difficult issues that must be dealt with in the near future and I believe we need leaders who are willing to make thoughtful and tough decisions about our country's future," Corker said in a release. "From my interaction with Scott DesJarlais, I believe he is willing to deal with those tough issues head on."

Blackburn said she is "proud to endorse Scott DesJarlais because he is a conservative fighter in the truest sense of the word. He will fight for Tennessee and against Washington-style big government. He believes in getting government out of the way so Tennessee businesses can start hiring again and he knows the reckless spending in Washington must come to an end."

The 4th District contest is attracting increased attention with CNN listing it among the top 50 vulnerable seats in the 435-member House.